In 1494, King Charles VIII of France invaded Italy. Within months, his army collapsed and fled. It was routed not by the Italian army but by a microbe. A mysterious new disease spread through sex killed many of Charles’s soldiers and left survivors weak and disfigured. French soldiers spread the disease across much of Europe, and then it moved into Africa and Asia. Many called it the French disease. The French called it the Italian disease. Arabs called it the Christian disease. Today, it is called syphilis.

I’ve been intrigued by the murky history of syphilis for a few years now. The text above is from the start of an article I wrote for Science in 2008. At the time, scientists were split between two explanations for sudden appearance of syphilis at the end of the fifteenth century. According to one, it was caused by bacteria that had evolved in the New World and were brought back to Europe by Columbus’s crew. But other researchers found many skeletons with signs of syphilis in Europe, Africa, and Asia that appeared to have been from long before Columbus’s voyage. They argued that it must have started in the Old World, perhaps before people even left for the New World some 15,000 years ago.

As I explained in the article, one way to test these hypotheses is to survey the evolution of the bacteria. A group of researchers based at Emory University came across bacteria infecting Indians in Guyana that was genetically close, but not identical, to syphilis. They suggested syphilis had evolved in the New World from a common ancestor of both pathogens. Columbus’s crew may have picked it up when they visited the New World and then brought it home to Europe. Unfortunately, by the time doctors had gotten the bacteria from the jungles of Guyana to a laboratory where it could be analyzed, the DNA was in bad shape, so they couldn’t come to a firm conclusion.

Recently, I caught up with one of the scientists on the team, Kristin Harper, who is now at Columbia University. She didn’t have any new genetic results to talk about, unfortunately, although she may before long. In the meantime, she pointed me to a new review she has published in the Yearbook of Physical Anthropology. She and her colleagues took a look at the bones that scientists have pointed to as evidence for the antiquity of syphilis in both the New and Old World, and passed judgment about just how good the evidence was that they did, indeed, have syphilis, and not some other disease that can deform bone. The scientists also took a close look at the dating of the bones, since the timing of syphilis’s origin is so crucial to the entire debate.

The trouble with a lot of past research, Harper says, is that scientists have come up with new ways to diagnose syphilis in ancient bones without offering good evidence that their criteria are good. “Paleopathology is kind of the wild west of science, in that the ‘rules’ are still in their infancy,” Harper said. “We set ourselves the challenge of using only evidence-based diagnostic criteria in this paper and tried to be similarly stringent about dating.”

The scientists looked at 54 reports from both hemispheres. Most of the Old World bones failed to meet at least one of the standard requirements for a diagnosis of syphilis, such as distinctive pits on the skull or swelling in the long bones of the arms and legs. But when they looked at the Old World bones that had been dated to before 1492 that did make the grade, they ended up throwing all of those bones out, too. The evidence that these Old World bones were from before 1492 turned out to be weak. They tended to come from coastal regions, where people eat lots of fish. Fish are full of carbon from deep in the ocean, which has a different balance of isotopes than that found on the land. The ocean carbon gets into the bones of coastal people, where it can throw off estimates of their age by centuries. A close examination of these coastal Old World bones led the Emory scientists to conclude that they belonged to Europeans who died shortly after Columbus’s voyage.

“In contrast,” Harper told me, “we found definite cases of treponemal disease [syphilis] hailing from the New World that stretched back thousands and thousands of years.”

Harper and her colleagues conclude that there’s no good evidence for syphilis in the Old World, and plenty in the New World. They continue to argue that syphilis traveled east across the Atlantic.

It’s intriguing if Harper turns out to be right. Europeans brought smallpox and other pathogens to the New World which decimated its residents. Syphilis, it seems, is one pathogen that went the other way.

It seems the last sentence is contradicted by the preceding 2 paragraphs. Reading the summary of the research, it sounds like no definitive proof of it existing in the New World, but lots of evidence historical from the Old World.

[CZ: Mark, I’m not sure how you’re reaching this interpretation. The scientists see evidence for ancient syphilis in the Old World. I’ve edited my piece to make sure this point is clearer.]

It’s hard to pinpoint an exact place of origin for syphilis and most STDs. The fifteenth century was also an age of exploration involving contact with previously isolated ecosystems across the world. That includes Africa, Asia, as well as North and South America. Not only did this mean new microorgamisms being introduced back and forth but also allowing these new organisms to mutate in unexpected ways as they entered new territories.

[CZ: If we accept Harper’s evidence, we can constrain the origin of syphilis. Archaeologists have found bones in the Old World outside of Europe that show signs of syphilis. But none come from before 1492. If syphilis was bouncing back and forth around the world for centuries before then, you might find it in the mummies of Egypt, which show signs of many diseases, such as smallpox.]

Actually, the paragraphs you site indicate that syphilis has definitely been in the New World for thousands of years, but there’s no reliable evidence that it existed in Europe prior to Columbus’s voyages. All the pre-1492 syphilitic bones in Europe are from coastal regions where they would have picked up an unusual carbon isotope profile from eating fish, throwing off attempts at radiocarbon dating.

#1 Mark you have it backwards for Syphilis. The research is indicating that all the old world examples of syphilis from before Columbus are dubious. But the New World examples before Columbus and the Old World after Columbus are not. Thus the idea that it was brought back from the New World to the old.

By the way, do we have any sources that indicate any of the New World groups were aware of a disease like syphilis?

The claim is interesting but the timing seems so short. That would mean that the disease managed to spread from someone returning on Columbus’s first voyage. It isn’t clear to me that any of the Europeans themselves would have had much opportunity to pick up the disease (although maybe someone who actually is an expert on the early voyages could comment on this more) which would suggest that it may have reach Europe by one of the people brought back to Europe by Columbus. There’s a secondary issue (which may just indicate my ignorance) but it seems odd given that Columbus stopped over in Portugal and then returned to Spain yet the first reports of the disease in Europe are in Italy. This may just be that the army gave it the first opportunity to spread far?

[CZ: Joshua–Thanks for catching the typo. Fixed it. As for your questions: 1. I don’t know of any source indicating an awareness of syphilis in the New World, but I could well be missing something. 2. As for timing, it doesn’t take very long to pick up syphilis. 3. The outbreak in Italy could have been preceded by much smaller outbreaks elsewhere in Europe that didn’t make it into the history books.]

Just to throw a monkey wrench in all these interpretations of Carl’s article: Could there have been some kind of horizontal gene transfer between two closely related bacteria? Suppose you had a mild but highly infectious New World bacterium, and a fatal but non-infectious* bacterium in the Old World? Put the two together in one urethra, and watch the sparks fly!

* What is the word for a bacterial infection that’s very difficult to get, but always nasty? I’m thinking, e.g., of flesh-eating bacteria.

[CZ: Horizontal gene transfer is always worth thinking about. And there are certainly non-STD relatives of the Treponema strain that causes syphilis. I think we’ll have to wait for a lot more Treponema genomes before we’ll get a better idea of the genetic history.]

Why is it that Columbus’ 1492 voyage is the focus of this question? Europeans had been traveling to the north western Atlantic coast for centuries (Norse settlements around 1000 CE. are one example) and would have had sufficient opportunity for contact with indigenous peoples. An alternate point of entry might help explain the larger observance around 1494 as well as some of the coastal remains.

[CZ: If Scandinavians brought syphilis back to Europe in 1000, you might expect syphilitic bones in the five centuries before Columbus’s voyage. Harper and her colleagues reject all the claims for such bones.]

Don’t forget that Columbus and his crew were not the first Europeans to cross the Atlantic and return. Has anyone considered whether the disease might have been brought back by the Vikings? They didn’t have much of a written tradition (apart from the sagas, which were written long after the event), but they did trade extensively over Europe – possibly explaining why the first documented accounts of the disease are found elsewhere.

@Romeo: “previously isolated ecosystems” – is this an example of Eurocentric bias? All of these ecosystems were on continents dominated by humans, so the only likely isolation is from caucasians, not from humans. We are almost certainly talking about ordinary human-to-human transmission of existing human diseases, i.e. disease migration and not disease origin. (I’ll grant that in many or even most cases the diseases will have migrated to Europe directly from their continent of origin – but a continent is a big place.)

Sypillis was much more virulent in the 16th century, when “new” in Europe,
compared to 19th century, when one survived for 10 to 20 years after
infection typically.
This is some “fact” I learned in the sixties, but is it really true?
Georg

[CZ: I recall this, too, but I’d need to check some sources to be sure. Certainly, it’s not unusual for pathogens to evolve to a differen level of virulence as they adapt to different ecosystems.]

One thing that was always troubling for me is the fact that Columbus returned from his first voyage in March of 1493 (and he visited Santo Domingo and Cuba, not the continent itself). In the end of February of 1495 Charles VIII’s army entered Naples where it apparently picked the disease. I understand how it got from Spain to Naples – King of Naples was a cousin to the King of Aragon and both countries were trading extensively.
However, I’m not that familiar with syphilis epidemiology – is it theoretically possible in a matter of two years to become a major epidemics? And if it was brought by Columbus’ crew – do any reports suggest that any of them died of this disease?

I’m not saying that New World theory is wrong, I’m just not sure of how it could happen in a matter of 23 months?

Very interesting; I’ve been reading conflicting reports for years. The evidence linking syphillis to theNew World is directly contrary to what we taught biology undergraduates at Cornell back in the late 1970s when I was a graduate student. I wonder if such students ought now be ‘recalled’ as defective.

The Norse inhabited parts of North America almost 500 years or more before Columbus arrived. That is a substantial amount of time for disease to spread. Is there any evidence of syphyllis that may have come via the northern route at an earlier time?

[CZ: No good evidence, according to the authors of the new review. Some folks have claimed that skeletons in England from before 1492 show signs of syphilis, for example, but the evidence doesn’t hold up well.]